Air circulation system

ABSTRACT

An air circulation system is provided for a building having a plurality of zones to be heated, ventilated or cooled. The system includes an air circulating apparatus arranged to supply either heated, cooled or ventilated supply air to the various zones of the building via a plurality of supply ducts. The apparatus also draws return air from the zones via a plurality of return ducts. A damper is coupled to both the supply and return ducts of each zone, adjacent the air circulating apparatus, to balance the amount of supply and return air in each zone for reducing mixing of air between zones and stratification within a zone. Accurate and independent control of each zone in relation to the other zones in the building is thus permitted. The circular ducts are formed of sealed PVC or other suitable plastic material to improve the efficiency of the air delivery system both by reducing pressure losses and temperature losses conducted through the walls of the ducts.

FIELD OF THE INVENTION

[0001] This invention relates to an air circulation system for buildingsand the like and more particularly to an air circulation system forheating or cooling purposes.

BACKGROUND

[0002] The use of an air circulation system in a building whichincorporates air heating or cooling is well known for controlling thetemperature, quality or quantity of air circulated within a building.The system usually incorporates a main blower which generates a flow ofheated or cooled air via metal supply ducts to various zones within thebuilding. Control of the temperature within the building is usuallyaccomplished by varying the cycle duration of cooling or heatingcomponents of the circulation system, as called for by a thermostat. Aplurality of return ducts returns air from the zones back to the blowerthrough a main plenum. Control of the amount of circulation in each zoneis usually accomplished by providing dampers in the branched runs and atthe diffusers at the terminal ends of the supply ducts. The rectangularshape of the plenums causing air turbulence and the arrangement of thedampers in the branched runs and at the diffusers of the supply ductshowever leads to substantial static pressure losses in the ducts andplenums. The conventional metal ducts are also known to leak due to thelimitations of the metal construction and have poor efficiency due tothe high conductivity of the metal. When drawing return air from thereturn ducts in such systems, the amount of air drawn from therespective zones of the building often varies uncontrollably, dependingupon leaks in the return ducts and the location of the return ducts inrelation to the blower, resulting in frequent and uncontrollable mixingof the air between zones and in zone stratification. This mixing orstratification results in a system which is inaccurate, difficult tocontrol and provides discomfort to the building occupants. Furtherproblems arise when it is desired to adjust the temperature or airquality of one zone in relation to another.

SUMMARY

[0003] According to one aspect of the present invention there isprovided a method of controlling air circulation in a building havingplural zones, the method comprising:

[0004] providing an air circulation apparatus having supply ductingarranged to discharge a flow of pressurised supply air from theapparatus and return ducting arranged to draw a flow of return air intothe apparatus;

[0005] providing at least one supply duct associated with each zone;

[0006] coupling each supply duct in communication between the supplyducting and the zone associated with the supply duct;

[0007] providing a damper on each supply duct adjacent to the supplyducting of the air circulation apparatus arranged to control the flow ofsupply air through the supply duct;

[0008] providing at least one return duct associated with each zone;

[0009] coupling each return duct in communication between the returnducting and the zone associated with the return duct;

[0010] providing a damper on each return duct adjacent to the returnducting of the air circulation apparatus arranged to control the flow ofreturn air through the return duct;

[0011] adjusting the dampers on the respective supply ducts such thateach zone receives a desired amount of the flow of supply air deliveredthereto;

[0012] adjusting the dampers on the respective return ducts such thatthe flow of return air through the return ducts of each zone issubstantially equal to the flow of supply air delivered through thesupply ducts to that zone.

[0013] The supply and return ducting of the air circulation apparatusmay comprise a manifold mounted directly on the respective take offplenum of the apparatus or in further embodiments, the ducting maydesignate collectively a manifold associated with each control regionand the ducts extending therebetween. Providing a damper on each ductpermits the control of flow through each duct dependent upon designneeds.

[0014] According to a second aspect of the present invention there isprovided an air circulation system for a building having a plurality ofzones, the system comprising:

[0015] an air circulation apparatus having a supply outlet arranged todischarge pressurised supply air from the apparatus and a return inletarranged to draw return air into the apparatus;

[0016] a supply manifold coupled to the supply outlet of the aircirculation apparatus;

[0017] at least one supply duct coupled in communication between eachzone and the supply manifold;

[0018] a damper coupled to each supply duct adjacent the supply manifoldand being arranged to control a flow of the supply air through thesupply duct;

[0019] a return manifold coupled to the return inlet of the aircirculation apparatus;

[0020] at least one return duct coupled in communication between eachzone and the return manifold;

[0021] a damper coupled to each return duct adjacent the return manifoldand being arranged to control a flow of the return air through thereturn duct.

[0022] According to a further aspect of the present invention there isprovided a building having at least one control region comprising aplurality of zones and an air circulation system comprising:

[0023] an air circulation apparatus having a supply outlet arranged todischarge pressurised supply air from the apparatus and a return inletarranged to draw return air into the apparatus;

[0024] said at least one control region having a supply manifoldassociated therewith, the supply manifold being coupled to the supplyoutlet of the air circulation apparatus;

[0025] at least one supply duct coupled in communication between eachzone of said at least one control region and the supply manifoldassociated with said at least one control region;

[0026] a damper coupled to each supply duct adjacent the supply manifoldof said at least one control region, the damper being arranged tocontrol a flow of the supply air through the supply duct;

[0027] said at least one control region having a return manifoldassociated therewith, the return manifold being coupled to the returninlet of the air circulation apparatus;

[0028] at least one return duct coupled in communication between eachzone of said at least one control region and the return manifoldassociated with said at least one control region;

[0029] a damper coupled to each return duct adjacent the respectivereturn manifold of said at least one control region, the damper beingarranged to control a flow of the return air through the return duct.

[0030] In practice, each control region of the building will generallycomprise a floor, a group of floors of the building or a designated wingof the building. The zones would thus generally comprise one or morerooms within each control region which are joined to form a generallycommon area. The supply or returns ducts associated with each zone maycomprise a single direct duct or may be branched adjacent to diffusersat the terminal ends to supply air to or draw air from different areasor rooms within the zone.

[0031] The use of dampers on both the supply and return ducts adjacentthe respective manifolds provides a convenient location to adjust all ofthe dampers of the system at one time for greater control of thedistribution of the air. The use of dampers on the return ducts inparticular permits the amount of supply air and return air in each zoneto be balanced to reduce mixing of air between zones. This enablesadjacent zones to have different air exchange rates and thus differenttemperatures in a heating or cooling system. Accurate and independentcontrol of each zone in relation to the other zones in the building isthus permitted dependent upon design needs.

[0032] The dampers on both the supply and return ducts are preferablycommonly located adjacent the air circulation apparatus.

[0033] The dampers of said at least one supply duct and the dampers ofthe respective said at least one return duct for each zone are arrangedsuch that the flow of supply air is approximately equal to the flow ofreturn air for each zone.

[0034] There may be provided a single dedicated supply duct and a singlededicated return duct for each zone. The dampers of each dedicatedsupply duct and the respective dedicated return duct for each zone wouldpreferably be arranged such that the flow of supply air is approximatelyequal to the flow of return air for each zone.

[0035] The supply ducts and the return ducts may each comprise a rigidtube of circular cross section which is formed of plastic material,preferably PVC material.

[0036] When using conventional PVC tubing, each of the supply and returnducts is formed of plural sections which are preferably sealedtherebetween such that the ducts each form a continuous sealed passagefrom the respective manifold to the respective zone.

[0037] There may be provided a boot on a free end of each supply andreturn duct arranged to mount the free end of the duct within asupporting surface of the respective zone. Each boot is preferably alsoformed of PVC material which is arranged to be mounted on the free endof the respective duct formed of PVC material in a sealed configurationtherebetween. Canvas collars may couple the plastic tubing to the bootsto allow for linear expansion and limit noise transfer due to vibration.

[0038] When the air circulation apparatus comprises a conventional airhandler for buildings, the supply and return manifolds are preferablyarranged to be mounted directly onto respective supply and return plenumtakeoffs of the air handler. The supply and return manifolds in thisarrangement are preferably adapted to mount the respective supply andreturn ducts formed of PVC material directly thereon. Alternatively, acanvas collar may be used at the transition point to mount the PVCmaterial onto the manifolds formed of metallic material, to allow fordiffering thermal expansion rates between the two materials, to allowfor linear expansion and to lessen noise.

[0039] The supply and return manifolds may include the dampers of therespective supply and return ducts mounted directly thereon.

[0040] When the air circulation apparatus is arranged to selectivelyheat the air, cool the air or both, a thermostat may be associated witheach zone. The thermostat could be arranged to control the respectivedampers associated with the zone to accordingly control a temperature ofthe zone.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In the accompanying drawings, which illustrate an exemplaryembodiment of the present invention:

[0042]FIG. 1 is schematic view of the air circulation system accordingto the present invention.

[0043]FIG. 2 is an isometric view of an air circulation apparatus foruse with the system of FIG. 1.

[0044]FIG. 3 is an alternative arrangement for an auxiliary manifoldwhich includes an adjustable damper plate.

[0045]FIG. 4 is an isometric view of the supply and return ducts in aportion of a building in a heating arrangement.

[0046]FIG. 5 is an isometric view of the supply and return ducts in aportion of a building in a cooling arrangement.

[0047]FIGS. 6A, 6B and 6C are isometric view of various arrangements ofboots arranged to mount the terminal end of a duct according to FIG. 1in a supporting surface such as a wall or floor and the like.

[0048]FIG. 7 is an elevational view of a collar mounting a terminal endof one of the ducts to a suitable mounting surface.

DETAILED DESCRIPTION

[0049] Referring to the accompanying drawings, there is illustrated anair circulation system generally indicated by reference numeral 10. Thesystem 10 is arranged for circulating air having a primary controlregion 12 comprised of plural zones 14 within which the temperature andflow of Heating, Ventilation and Air Conditioning (HVAC) airtherethrough are to be regulated. The system 10 may also be adapted foruse with a building having one or more auxiliary control regions 16which is also comprised of plural zones 14 to be regulated. Each controlregion of the building may comprise a floor, a group of floors of thebuilding or a designated wing of the building whereas the zonesgenerally comprise one or more rooms of the building which are joined toform a generally common area.

[0050] The system 10 includes an air handler which is similar toconventional HVAC units. The air handler 18 includes a supply outletdefined by a supply plenum takeoff 20 for discharging a flow ofpressurised supply air therethrough. A return inlet is also provided inthe form of a return plenum takeoff 22 which is arranged to draw a flowof return air therethrough. A supply manifold 24 and a return manifold26 are arranged to be mounted on the respective supply and return plenumtakeoffs in place of the plenums found in a conventional system.

[0051] Within the primary control region 12, one or more supply ducts 28is coupled between each zone and the supply manifold 24. Accordingly,within the primary control region, one or more return ducts 30 isconnected between each zone 14 and the return manifold 26. Each duct isarranged to communicate directly between the respective manifold and therespective zone associated therewith. It is preferable to have a singlededicated supply duct in a single dedicated return duct for each zonefor optimal control of the air flow through the zone, however it may bemore economical to have a single return duct associated with pluralsupply ducts when the zone comprises a large open area encompassingseveral rooms.

[0052] Each duct 28 or 30 may also include one or more branched sections31 adjacent to the diffusers at the terminal ends of the ducts to supplyair to or draw air from one or more areas or rooms within a zone. Eachindividual branched section would include an additional damper thereinto be adjusted upon initial installation.

[0053] A damper 32 is coupled to each duct 28 and 30 adjacent therespective manifold which is arranged to mount the damper thereon. In abuilding having a single primary region 12 both the supply and returndampers are commonly located adjacent the air handler 18.

[0054] When the building includes one or more auxiliary regions 16 anauxiliary supply manifold 34 and an auxiliary return manifold 36 areassociated with each region 16. The auxiliary manifolds are locatedadjacent the respective auxiliary region associated therewith remotelyfrom the air handler 18. An oversized duct 38 communicates between eachauxiliary manifold and the respective plenum takeoff 20 or 22. Supplyand return ducts are arranged in the auxiliary regions and coupledbetween each zone of the region and the respective auxiliary manifold ina similar manner as in the primary region 12 with dampers being locatedon each duct adjacent the respective manifold.

[0055] As illustrated in FIG. 3, an alternate auxiliary manifold 108 isprovided for use when the oversized duct 38 is branched into two ducts28. An adjustable damper plate 110 is pivotally mounted between theducts 28 at the manifold 108 to vary the amount of air diverted to eachduct. A control rod 112 is provided to adjust the position of the damperplate.

[0056] Each of the ducts are formed of conventional PVC pipe which isrigid and circular in cross section. The supply and return manifolds 24and 26 are adapted to mount the PVC pipe directly thereon. Asillustrated in FIG. 7, a canvas collar 100 may be provided for mountinga terminal end of one of the ducts designated by reference numeral 102,to a suitable mounting surface 104, which may comprise either a boot asillustrated in FIG. 6 and described in the following or one of themanifolds 24 or 26.

[0057] The ducts are thus assembled from pre-formed sections which aresealed upon assembly between each respective section so as to form acontinuous sealed passage between the respective manifold and therespective zone associated therewith. As illustrated in FIG. 4, theoversized duct 38, which may act as an auxiliary manifold, can also beformed of tubular PVC material.

[0058] As illustrated in FIGS. 6A through 6C, various boots 40 areillustrated for mounting on the respective terminal free ends of thesupply and return ducts. Each boot is formed of PVC material similarlyto the ducts for securement thereto in a sealed configuration usingappropriate sealant. Each boot includes an appropriate male connector 42or female connector 44 for mounting on the terminal free end of therespective duct. The boots are thus adapted to mount the free ends ofthe respective ducts in an appropriate supporting surface such as a wallor floor of the appropriate zone associated therewith. As describedabove in regard to FIG. 7, the boots may also incorporate canvas collars100 at the transition point between the ducts and the boots.

[0059] The control of the dampers 32 may be arranged manually or througha control system 46. When manually adjusting the dampers the overallflow requirements of the building to achieve the required heating orcooling within the respective zones of the building must first bedetermined. With the dampers initially all opened approximately only ¾of their fully opened position, an operator may manually partially closeselected dampers on the supply ducts 28 to any desired degree to achievea desired flow of supply air to each zone of the building.

[0060] Subsequently each damper on the return ducts 30 is then partiallyclosed by a desired amount to achieve a balance between the flow ofreturn air from each zone with the flow of supply air to that zone.Further adjustment of selected dampers on both the supply and returnducts may be then required to ensure that the combined flow of supplyair through all supply ducts in a given zone is substantially equal tothe combined flow of return air through all return ducts within thatzone.

[0061] When using a single dedicated supply and a single dedicatedreturn duct within each zone the damper on the respective supply duct isarranged similarly to the damper on the respective return duct in orderto achieve a balance of supply air and return air within a given zone.

[0062] To monitor the use of the air circulation system, a controlsystem 46 employing programmable logic controllers may be used. Thecontrol system 46 would include a thermostat 48 located within each zone14 of the building. The thermostats 48 would be arranged to monitor thetemperature within the respective zones and relay appropriate controlsignals back to the control system 46 which would then actively open orclose selected supply and return dampers to adjust the amount of heatingor cooling air being supplied to a given zone. Flow meters could beincorporated into the system to ensure that the flow of return air issubstantially equal to the flow of supply air within each selected zoneregardless of the different flow requirements among the different zones.

[0063] The air circulation system 10 is intended to be a complete airdelivery system which includes both a heating and cooling source. Thefirst step in setting up the system 10 is to perform heat loss or heatgain calculations (as per most North American Building Codes). Thegeographical location will determine which calculation is necessary,heat loss or heat gain. From that calculation the heating and/or coolingcapacities can be determined. The total air volume of the aircirculation system 10 can then be determined by the desired heat riseand/or heat fall necessary for a particular geographic location.

[0064] Ideally the air circulation system 10 would utilise a horizontalfurnace/air handler to avoid pressure losses from the typical threetransitions which are a product of the standard upright version. Tosimplify the understanding of the air circulation system 10, an uprightfurnace/air handler is described and illustrated as these are the mostpopular style.

[0065] The air circulation system 10 incorporates a custom-made,galvanized steel, vertical supply air plenum or bonnet adapted to mountdirectly on the air handler 18. The supply air plenum comprising thesupply manifold 24 incorporates turning vanes and/or a gentle cornerwith an inside radius of at least ⅓ of the duct width to reduce pressureloss. The vertical return air plenum comprising the return manifold 26will also be made of galvanized steel and includes the same pressureloss reduction methods of vanes and/or gentle tapering at eachtransition. Both the supply and return plenums may be insulated to lowertempering losses through the conductive metal. The air handler includesa fan motor which is preferably of the centrifugal or ECM type.

[0066] At the metal supply and return air vertical plenums, a transitionwill take place to solid round ducting, preferably plastics, for examplePVC tubing and the like. This transition will take place through thedampers 32 formed of metal on both the supply and return air verticalplenums to carefully control air flow. The supply air plenum mayincorporate a plenum box creating a small horizontal facet to thevertical plenum dependent on furnace/air handler orientation. The solidducting (supply and return) will be completely sealed (preferably glued)right to its targeted zone.

[0067] Transition fittings will be at 45° maximum where possible tominimize pressure losses. Sealing (preferably gluing) is necessary tolimit air pressure losses, air mixing, dirt infiltration and supply andreturn air imbalances. Plastics are the preferred duct medium because ofthe limited conductive heating and/or cooling losses. The round ductingallows for a reduction of air friction losses due to turbulence causedby rectangular ducts. Round plastic ducting further reduces air frictionbecause of it's smooth nature, as compared to conventional metal andthus will not accumulate dust and dirt as readily.

[0068] The locations of the air distribution supplies and returns arevital to efficient operation and occupant comfort in the air circulationsystem 10. For geographic regions where the primary function of the aircirculation system 10 is heating, a duct arrangement for a given zone inthe system is indicated generally by reference numeral 60 in FIG. 4. Forgeographic regions where the primary function of the air circulationsystem 10 is cooling, a duct arrangement for a given zone in the systemis indicated generally by reference numeral 72 in FIG. 5.

[0069] As illustrated in FIG. 4 for heating, the supply outlets 62should be located in the floor at the outside wall 64, underneath awindow 66 where applicable. This outlet location, together with adiffuser which provides a wide spread in the air jet pattern, will allowfor a consistent dilution of the cool air in the stagnant region. Coldair return 68 locations should be at floor levels on side walls 70opposite to that of the supply, to remove the cooler air from thestagnant area in that particular zone.

[0070] As illustrated in FIG. 5 for cooling, the supply outlets 74should be mounted high on partition walls 76 opposite the outside walls78 and/or windows 80 and utilise a diffuser with a non-spreading air jetpattern. That combination of the proper location and type of outlet willallow for consistent dilution of the hot air in the stagnant area. Thehot air return 82 locations should also be high on a partition wall 76,very close to the outside wall 78 and as far from the supply outlet 74as possible, to remove hot air from the stagnant area in that particularzone.

[0071] In geographic regions where heating and cooling functions areperformed by the air circulation system, the heating duct arrangement 60of FIG. 4 for supply outlet 62 and return outlet 68 locations should beutilised, with the air handler incorporating a 2 speed fan motor whichcan operate on a high speed in the cooling season. Supply air outlets 62should be utilised which have both a heating and cooling position. Theheating position comprises a wide spreading pattern while the coolingposition comprises a non-spreading air distribution pattern.

[0072] The intent of the air circulation system 10 is to relay hot orcold air from a supply source to a targeted destination or zone of abuilding in an efficient and accurate manner. The air is relayed througha low air resistance medium that also conserves the air temperature.System accuracy comes from controlled supply and return air flowsthrough dampers on both the supply and return vertical plenums right atthe air handler 18. The system 10 will better serve building zones withgreater heating or cooling losses, reducing stratification effects andinstances of differential temperatures in areas on the same level of abuilding. Tempered air can be relayed effectively and efficientlythrough to 2nd floor areas and other auxiliary control regions.Heating/cooling and air flow losses are minimised because of the lowthermal conductivity of the air transfer medium and the method ofinstallation. The air circulation system 10 allows heating/coolingsources to be properly sized because of the ability to distribute thetempered air effectively and efficiently to targeted zones. When airhandlers of conventional heating, ventilating and air conditioningsystems are replaced with the air circulation system 10, the size of theheating/cooling source can be reduced in many instances.

[0073] The air circulation system 10 is advantageous in many ways as itcan improve building occupant comfort, reduce utility costs, produce acleaner living or working environment and reduce greenhouse gasemissions. Accuracy is accomplished by the ability to damper both thesupply and return air ducts at the source. This will allow properquantities of heating or cooling air to be delivered to different areasof a building dependent on requirements, creating a controllable system.Heating and/or cooling system response times can be instantaneous andventilation air will be delivered more accurately to the building.Automatic zone control and/or zone customising can be easily performedto provide variations suited to one's own personal needs. For example,an elderly parent living together with his or her children may requireadditional heat.

[0074] Selection of PVC duct material provides that duct temperaturelosses are minimised due to the low thermal-conductivity of the plasticducts. Since the system is sealed, the only dirt, dust that will enterwill be directly from the targeted area. The air circulation system willalso not accumulate as much dust and dirt as conventional systemsbecause of it's smooth nature. Furthermore the ducting material will notdeteriorate under varying environmental conditions like: salt water air,high humidity. The PVC ducts are also comparable in cost to aconventional metallic duct system.

[0075] While one embodiment of the present invention has been describedin the foregoing, it is to be understood that other embodiments arepossible within the scope of the invention. The invention is to beconsidered limited solely by the scope of the appended claims.

1. A method of controlling air circulation in a building having pluralzones, the method comprising: providing an air circulation apparatushaving supply ducting arranged to discharge a flow of pressurised supplyair from the apparatus and return ducting arranged to draw a flow ofreturn air into the apparatus; providing at least one supply ductassociated with each zone; coupling each supply duct in communicationbetween the supply ducting and the zone associated with the supply duct;providing a damper on each supply duct adjacent to the supply ducting ofthe air circulation apparatus arranged to control the flow of supply airthrough the supply duct; providing at least one return duct associatedwith each zone; coupling each return duct in communication between thereturn ducting and the zone associated with the return duct; providing adamper on each return duct adjacent to the return ducting of the aircirculation apparatus arranged to control the flow of return air throughthe return duct; adjusting the dampers on the respective supply ductssuch that each zone receives a desired amount of the flow of supply airdelivered thereto; adjusting the dampers on the respective return ductssuch that the flow of return air through the return ducts of each zoneis substantially equal to the flow of supply air delivered through thesupply ducts to that zone.
 2. An air circulation system for a buildinghaving a plurality of zones, the system comprising: an air circulationapparatus having a supply outlet arranged to discharge pressurisedsupply air from the apparatus and a return inlet arranged to draw returnair into the apparatus; a supply manifold coupled to the supply outletof the air circulation apparatus; at least one supply duct coupled incommunication between each zone and the supply manifold; a dampercoupled to each supply duct adjacent the supply manifold and beingarranged to control a flow of the supply air through the supply duct; areturn manifold coupled to the return inlet of the air circulationapparatus; at least one return duct coupled in communication betweeneach zone and the return manifold; a damper coupled to each return ductadjacent the return manifold and being arranged to control a flow of thereturn air through the return duct.
 3. The system according to claim 2wherein the dampers on the supply ducts are commonly located adjacentthe air circulation apparatus.
 4. The system according to claim 2wherein the dampers on the return ducts are commonly located adjacentthe air circulation apparatus.
 5. The system according to claim 2wherein the dampers on both the supply and return ducts are commonlylocated adjacent the air circulation apparatus.
 6. The system accordingto claim 2 wherein the dampers of said at least one supply duct and thedampers of the respective said at least one return duct for each zoneare arranged such that the flow of supply air is approximately equal tothe flow of return air for each zone.
 7. The system according to claim 2wherein there is provided a single dedicated supply duct and a singlededicated return duct for each zone.
 8. The system according to claim 7wherein the dampers of each dedicated supply duct and the respectivededicated return duct for each zone are arranged such that the flow ofsupply air is approximately equal to the flow of return air for eachzone.
 9. The system according to claim 2 wherein the supply ducts andthe return ducts each comprise a rigid tube of circular cross sectionwhich is formed of plastic material.
 10. The system according to claim 9wherein each of the supply and return ducts are formed of pluralsections which are sealed therebetween such that the ducts each form acontinuous sealed passage from the respective manifold to the respectivezone.
 11. The system according to claim 9 wherein the ducts are formedof PVC material.
 12. The system according to claim 11 wherein there isprovided a boot on a free end of each supply and return duct arranged tomount the free end of the duct formed of PVC tubing within a supportingsurface of the respective zone.
 13. The system according to claim 12wherein each boot is formed of PVC material and arranged to be mountedon the free end of the respective duct in a sealed configurationtherebetween.
 14. The system according to claim 2 wherein the aircirculation apparatus comprises a conventional air handler for buildingsand wherein the supply and return manifolds are arranged to be mounteddirectly onto respective supply and return plenum takeoffs of the airhandler.
 15. The system according to claim 14 wherein the supply andreturn ducts comprise conventional PVC tubing and the supply and returnmanifolds are adapted to mount the respective supply and return ductsdirectly thereon.
 16. The system according to claim 15 wherein thesupply and return manifolds include the dampers of the respective supplyand return ducts mounted directly thereon.
 17. The system according toclaim 2 wherein the air circulation apparatus is arranged for heatingthe air and wherein there is provided a thermostat associated with eachzone arranged to control the respective dampers associated with the zoneto control a temperature of the zone.
 18. The system according to claim2 wherein the air circulation apparatus is arranged for cooling the airand wherein there is provided a thermostat associated with each zonearranged to control the respective dampers associated with the zone tocontrol a temperature of the zone.
 19. The system according to claim 2wherein the air circulation apparatus is arranged to selectively heatand cool the air and wherein there is provided a thermostat associatedwith each zone arranged to control the respective dampers associatedwith the zone to control a temperature of the zone.
 20. A buildinghaving at least one control region comprising a plurality of zones andan air circulation system comprising: an air circulation apparatushaving a supply outlet arranged to discharge pressurised supply air fromthe apparatus and a return inlet arranged to draw return air into theapparatus; said at least one control region having a supply manifoldassociated therewith, the supply manifold being coupled to the supplyoutlet of the air circulation apparatus; at least one supply ductcoupled in communication between each zone of said at least one controlregion and the supply manifold associated with said at least one controlregion; a damper coupled to each supply duct adjacent the supplymanifold of said at least one control region, the damper being arrangedto control a flow of the supply air through the supply duct; said atleast one control region having a return manifold associated therewith,the return manifold being coupled to the return inlet of the aircirculation apparatus; at least one return duct coupled in communicationbetween each zone of said at least one control region and the returnmanifold associated with said at least one control region; a dampercoupled to each return duct adjacent the respective return manifold ofsaid at least one control region, the damper being arranged to control aflow of the return air through the return duct.